Exosome Diagnostics’ technology able to detect T790M mutation in intra-thoracic patients; detection in this subpopulation has proven challenging with cfDNA-only liquid biopsy platforms

CAMBRIDGE, Mass., August 5, 2015 – Exosome Diagnostics, Inc., a developer of revolutionary, biofluid-based molecular diagnostics, today announced data demonstrating the ability of its proprietary exosomal RNA (exoRNA) plus cell-free DNA (cfDNA) platform to detect with high sensitivity EGFR activating mutations and the EGFR T790M resistance mutation in blood plasma of patients with non-small cell lung cancer (NSCLC). The data were presented at a poster session on Friday, July 31, 2015, titled, “Detection of EGFR activating and T790M resistance mutation in plasma of NSCLC patients using combined exosomal RNA and cfDNA capture,” at the 16th Annual International Lung Cancer Congress, which took place July 30 – August 1, 2015 in Huntington Beach, Calif.

“Unfortunately, non-small cell lung cancer is very smart; it develops new mutations over time to resist treatment, including the EGFR T790M mutation,” said Vince O’Neill, M.D., Chief Medical Officer at Exosome Diagnostics. “Based on these new data we presented, we’re highly encouraged that our EGFR T790M test will give medical oncologists a critical new tool to non-invasively and with high sensitivity detect the development of this resistance mutation over time through a simple blood draw, helping inform the most appropriate, targeted and timely treatment decisions for patients as their disease progresses.”

In the study, Exosome Diagnostics applied its exoRNA plus cfDNA platform to isolate 21 blood plasma samples from NSCLC patients collected at the time of clinical resistance to EGFR tyrosine kinase inhibitor (TKI) therapy. The samples were EGFR-genotyped on time-matched tissue from a repeat biopsy. The exoRNA and cfDNA were then simultaneously analyzed utilizing targeted ultra-deep sequencing (UDS) of select genes. The positive concordance of EGFR mutations in metastatic disease was 87 percent for the activating mutations (EGFR L858R and del19) and 82 percent for the resistance EGFR T790M mutation. In patients with intra-thoracic disease, these mutations have proven challenging to detect utilizing cfDNA alone. However, by combining exoRNA and cfDNA, Exosome Diagnostics achieved a 67 percent concordance for activating mutations and 40 percent for T790M.

“We’re particularly pleased that our exoRNA plus cfDNA platform demonstrated strong detection of patients with intra-thoracic disease, a subpopulation in which cfDNA-only liquid biopsy platforms have had difficulty detecting the T790M mutation,” said Dr. O’Neill. “This provides further evidence of the tremendous and clinically significant benefits of utilizing exoRNA as a source of molecular information for accurate mutation detection in cancer.”

Patients with EGFR activating mutations often initially respond to treatment with TKIs. However, eventually, many patients’ lung cancer continues to progress because they develop new, also known as acquired, mutations, including the T790M resistance mutation. Due to these acquired mutations, many patients stop responding to TKI therapy, rendering it ineffective. There are currently several therapies in clinical development that target these acquired mutations in NSCLC.

A critical step in matching patients to the most appropriate therapy or clinical trial is being able to detect these mutations as they develop. Molecular tests that require tissue biopsy present several drawbacks. Tissue biopsy provides molecular information about a tumor only at one static point in time. It becomes untenable to do repeat biopsies on NSCLC patients over time, particularly as the disease progresses. In addition, there are issues related to tissue availability and tumor heterogeneity; the tissue extracted during the biopsy may not reflect the complete molecular make-up of the tumor. Biofluid-based molecular diagnostics enable serial, longitudinal monitoring; clinicians can take repeated snapshots of disease throughout treatment, monitoring for drug resistance and emerging mutations in real-time and adjusting treatment course as necessary. In addition, biofluid samples, such as plasma or urine, are more readily available than tissue samples, and are accessible non-invasively.

About the Technology

Exosome Diagnostics’ T790M plasma-based liquid biopsy test is being designed to utilize the company’s proprietary, patented exosome-based technology to detect the presence of the EGFR T790M resistance mutation in patients with NSCLC by co-capture and co-analysis of exosomal RNA (exoRNA) and cell-free DNA (cfDNA). Exosomes are messengers released by all living cells into biofluids, such as plasma/serum, urine, cerebrospinal fluid and saliva. Exosomes contain RNA, DNA and proteins from their cell of origin. Exosome Diagnostics’ technology platform can achieve real-time access to comprehensive molecular information about cells in the body without direct access to the actual cells. The company’s platform is uniquely versatile, enabling the development of tests that can analyze either exoRNA alone or, when appropriate, simultaneously isolate and analyze exoRNA and cfDNA to enhance detection of rare mutations.

The EGFR T790M liquid biopsy will launch as a laboratory developed test in the company’s certified CLIA laboratory in 2015.

About Exosome Diagnostics

Exosome Diagnostics is a privately held company focused on developing and commercializing revolutionary biofluid-based diagnostics to deliver personalized precision healthcare that improves lives. The company’s novel exosome-based technology platform can yield comprehensive and dynamic molecular insights to transform how cancer and other serious diseases are detected, diagnosed, treated and monitored. Visit www.exosomedx.com to learn more.